This invention relates to backflow preventers.
Backflow preventers, examples of which can be found in U.S. Pat. Nos. 4,878,515, 4,044,787 and 3,918,477, are principally used for preventing contamination of a public water distribution system by preventing backflow or back-siphonage of contaminated water into the system. Usually, the backflow preventer assembly is installed in a pipeline between a main supply line and a service line that feeds an installation, e.g. hotels, factories or other institutions, or even a multi or single family residence.
A backflow prevention assembly may typically include one or several test cocks, e.g. standard ball valves, to allow service personnel to test the performance of a backflow preventer, e.g. during maintenance or repair.